Methods for improving the productivity of oil producing wells

Abstract

Methods for treating clastic formations bearing brine and at least one of black oil or volatile oil using a composition containing a nonionic polymer and solvent. The solvent at least one of solubilizes or displaces at least one of brine or oil in the clastic formation. Methods for treating a formation having at least one fracture using a composition containing a nonionic polymer and solvent. Methods for making a composition for treating a clastic formation bearing brine and at least one of black oil or volatile oil.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a national stage filing under 35 U.S.C. 371 of PCT / US2008 / 084719, filed Nov. 25, 2008, which claims priority to U.S. Provisional Application No. 60 / 991,590, filed Nov. 30, 2007, the disclosure of which is incorporated by reference in its entirety herein.BACKGROUND ART[0002]It is known in the subterranean well drilling art that in some wells (e.g., some oil wells) brine is present in hydrocarbon-bearing geological formations in the vicinity of the wellbore (also known in the art as the “near wellbore region”). The brine may be naturally occurring (e.g., connate water) and / or may be a result of operations conducted on the well.[0003]In the case of some wells (e.g., some oil wells), two phases (i.e., an oil phase and a gas phase) may form in the near wellbore region as the pressure falls below the saturation pressure (bubble point) of the oil. The presence of gas can cause a large decrease in relative permeability to oil,...

AI Technical Summary

Benefits of technology

[0060]each q is independently an integer of from 0 to about 55,wherein the solvent at least one of at least partially solubilizes or at least partially displaces at least one of the oil or the brine in the fracture, and wherein after the composition contacts at least one of the fracture or at least a portion of the plurality of proppants, the conductivity of the fracture is increased. In some embodiments, the formation is a clastic formation. In some embodiments, the formation is a nonclastic formation. In some embodiments, the oil is volatile oil. In some embodiments, the solvent comprises at least one of a polyol or polyol ether, wherein the polyol and polyol ether independently have from 2 to 25 carbon atoms. In some embodiments, the solvent comprises at least one monohydroxy alcohol, ether, or ketone, each independently having up to 4 carbon atoms. In some embodiments, the method further comprises contacting the fracture with a fluid prior to contacting the fracture with the composition, wherein the fluid at least one of at least partially solubilizes or at least partially displaces the brine in the fracture. In some embodiments, Rf is perfluorobutyl.

[0062]Treatment methods according to the present disclosure are typically useful, for example, for increasing the productivity of oil wells that have brine and / or have a gas present in a near wellbore region of a oil-bearing formation. Typically, after treatment according to the present disclosure, oil is obtained from the wellbore at an increased rate, as compared the rate prior to treatment. The treatment methods disclosed herein increase at least the oil permeability of the formation by at least 25, 50, 75, 100, 125, 150, 175, or even at least 200 percent. In some embodiments, the treatment methods disclosed herein increase at least the oil permeability of the formation by at least 160, 165, 170, 175, 180, 185, 190, or even at least 200 percent. Typically, and surprisingly, the compositions disclosed herein are even more effective for treating formations (e.g., clastic formations) bearing brine and oil (in some embodiments, volatile oil) than for treating formations having brine and retrograde condensate.

Problems solved by technology

The presence of gas can cause a large decrease in relative permeability to oil, and thus the productivity of the well decreases.

The presence of brine and / or the presence of two phases in a near wellbore region of an oil well can inhibit or stop production of hydrocarbons from the well, and hence is typically undesirable.

Conventional treatments for increasing the hydrocarbon production from such wells (e.g., a fracturing and propping operation or a solvent flush) often achieve limited success.

For example, fluids used in a fracturing operation can be difficult to clean up once the operation has been carried out.

Images